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Toke said:
I would say your analogy is a bit weak. :D

Why don't you find some examples of steel buildings that have burned for hours without collapsing? :)
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Must be a typo. I think you want me to find a steel building that burnt for hours and totally collapsed???
...well, I think somewhere was that warehouse full of fuel with an unprotected roof. The roof collapsed.

I mean, otherwise...
beijingtorch.jpg
 
pgimeno said:
It "wants to go up" because the density of the hot gas is less. The overpressure due to the deflagration exceeded atmospheric pressure by far, so the effect of atmospheric pressure over that heated gas (which is what would make it ascend) was overly compensated by the downward pressure.

If you observe the impacts, you can see that the lower part of the fireball extends downwards initially because of that effect. If you do that in a tube (like the elevator shaft) instead of in open air, the effect is much bigger.
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Absolutely right! You even can calculate how far it goes. I mean you have an overpressure of 3psi of 50% of that cube of burning gas right above the shaft... If it expanded to the double height then you still have 1.5psi overpressure or to 4 times that height at 0.75psi overpressure and so on. ...presuming that no doors were blown and the pressure could not escape.

But if the pressure could not escape at all than you can compress the air in the express shafts down to 77 and get an overpressure of 3psi in the entire shaft IF you have enough compressed volume above that shaft because otherwise...
 
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achimspok said:
Burning fuel do not explode, right? The overpressure of 3psi (NIST estimate) would be able to compress all the air in the elevator shafts down to the 77th floor. After that the air would decompress and blow the vapor upwards or it lost a lot of pressure through blown elevator doors reported down to the - surprise - 77th floor (and in the lobby of course - the local shafts opposite to the west entrance).
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I don't think your figures are accurate. The fireball in open air already went as low as floor 77, so in a closed cavity such as that of the elevator shaft, the pressure should have pushed it much further. I don't see a problem with it reaching the basement.

And here's yet another possibility: an unburned dropping of unpulverized fuel could fall through the shaft and get pulverized upon impact with the bottom, then ignited.

achimspok said:
Must be a typo. I think you want me to find a steel building that burnt for hours and totally collapsed???
...well, I think somewhere was that warehouse full of fuel with an unprotected roof. The roof collapsed.

I mean, otherwise...
[qimg]http://img375.imageshack.us/img375/8867/beijingtorch.jpg[/qimg]
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And what about the steel perimeter columns of the Windsor building in Madrid?

windsor-antes.jpg

windsor-despues.jpg


The fire caused the collapse in few minutes since the steel was reached by fire. This shows one side collapsed and the other one, not yet reached by fire, still intact:

windsor-durante.jpg


And that was with air's refrigeration.

The core was made of concrete.
 
achimspok said:
Well, once upon a time the church had no alternatives to an earth in the center of the world. So how many possibilities do we have?

Let's see, the NIST Interim Report had a theory about a buckled column 79 but also stated that column 79 only would buckle over an unsupported length of at least 4 floors if the steel temperature reaches 500°C.
Well, that seems to be pretty impossible for columns of a 3h fire resistance rating in the fuel lacking core area and an office space that burned away within about 20 minutes per area.
After years of hard work to animate fires at the SEC floors - guiding the fires by opening windows - setting up little fires in the north to "simulate" the spreading that didn't occur in the model - copying floors on fire and paste it one above the other - they got an surprising result: somehow the area around column 79 burnt for hours one floor above the other.
...and another surprise: 5 floors of unsupported column length and a steel temperature of above 150° (even if the report found no evidence for fire in the west of e.g. the 12th floor after 3:13pm).

So how many possibilities are left?
Whats about noodling column 79 for example in the basement near those strange hot spots found by AVIRIS?

No, whats about noodling column 81 and 80 for example in the basement near those strange hot spots found by AVIRIS? (...just because 80 and 81 must have been gone prior to 79.)
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Yes, there is one more possibility. You have not read the final report and do not understand the collapsse scenario.
 
achimspok said:
You are absolutely right, Bill! I say, one column is enough to bring WTC7 down. Zapp and BANG! These twoofers should first try to unprove it, right? Man, the steel is gone and hey, NIST is on our side, PM is on our side, even Zelikow and FOX is on our side. Let these ragheads burn in hell!
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I wonder how all four widely seperated corners of WTC7 dropped at the same time in NIST's 'progressive collapse' ?
 
pgimeno said:
I don't think your figures are accurate. The fireball in open air already went as low as floor 77, so in a closed cavity such as that of the elevator shaft, the pressure should have pushed it much further. I don't see a problem with it reaching the basement.
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Right, the WTC2 fireball reached down to the 77th floor of WTC1.
...but in the end it doesn't matter. The compressed volume will expand in any opening it will find - all shafts up and down and out of all blown windows. So you have a distinct volume to expand it into one shaft and those express shafts were very very long.

pgimeno said:
And here's yet another possibility: an unburned dropping of unpulverized fuel could fall through the shaft and get pulverized upon impact with the bottom, then ignited.
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Not a very good idea.
dropdeform.gif


pgimeno said:
And what about the steel perimeter columns of the Windsor building in Madrid? ... The fire caused the collapse in few minutes since the steel was reached by fire. This shows one side collapsed and the other one, not yet reached by fire, still intact:
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I see, it totally collapsed in free fall. ...or was it a pancake?

Btw, the fire burned for almost a day. The first collapse occurred after about 90minutes. The concrete core was the load carrying system I guess. The perimeter "light weight" steel structure was really not comparable. Furthermore we deal with
* a lack of a sprinkler system
* an incorrect installation of spandrels and
* a lack of fire prevention regulations in Spain

By all of that you got a series of partial collapses over hours and still a little bit of it remained standing.
 
funk de fino said:
Yes, there is one more possibility. You have not read the final report and do not understand the collapsse scenario.
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No, I read Brother Grimm meanwhile. Do you understand the collapse?

If so then please tell me why the north wall of the east penthouse collapsed and opened the view of the beautiful sky. Where was the south wall of the East Penthouse gone that previously rested right in the middle between column 80 and 81?
And maybe you can tell me why 9 columns below the west penthouse dropped within the duration of one NTSC frame simultaneously - from zero velocity into free fall without transition?
Maybe you know the meaning of those strange darting flames minutes before the collapse or you know something about that heavy smoke from the north side at about 5pm.
Maybe you know why the area near column79 burnt much longer than any other area (at least in the simulation).
And why Mr. Sunder never heard about the witnesses of "BABOOM!" sounds. Maybe you can tell me the mechanism that caused the building to sway west while a column in the east is buckling.

Well these are just my essential questions for a basic understanding without going into detail that much.

Are you surprised that the Interim Report exactly predicted the result of that biggest FEA of all times?
 
bill smith said:
I wonder how all four widely seperated corners of WTC7 dropped at the same time in NIST's 'progressive collapse' ?
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I wonder too but you have to read the report! It all started with a ballet of steel members...
ani3.gif

...and then there was that Tinytoon chain reaction, you know? Everything went down - all four widely separated corners within 0.3 seconds but...

First, the core fell down while the middle of the north face bowed towards south as you can see...
nistani5.gif


Oh, you can't? Must be the wrong picture. Sorry.

I wonder if de fino knows how that avalanche could crush the entire core without breaking any windows or even some dust. I think the time was too short. The east penthouse dropped like a stone through the building and just reached the ground then the west penthouse dropped in free fall and just reached the roofline when everything started to move in free fall too. I think there wasn't much time for that funny avalanche. Any idea?
 
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achimspok said:
I wonder too but you have to read the report! It all started with a ballet of steel members...
[qimg]http://img186.imageshack.us/img186/2959/ani3.gif[/qimg]
...and then there was that Tinytoon chain reaction, you know? Everything went down - all four widely separated corners within 0.3 seconds but...

First, the core fell down while the middle of the north face bowed towards south as you can see...
[qimg]http://img534.imageshack.us/img534/3061/nistani5.gif[/qimg]

Oh, you can't? Must be the wrong picture. Sorry.

I wonder if de fino knows how that avalanche could crush the entire core without breaking any windows or even some dust. I think the time was too short. The east penthouse dropped like a stone through the building and just reached the ground then the west penthouse dropped in free fall and just reached the roofline when everything started to move in free fall too. I think there wasn't much time for that funny avalanche. Any idea?
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No.sorry. Do you have any idea why they would have dropped the penthouses first ? If there is no good structural reason could it be that there was something in the penthouses that they did not want on the top of the pile ?
 
Folks,

 :eusa_shhh: Shhhhhhhhh.....

If you want to observe them in their native habitat, you must learn to sit very, very quietly...


Tom

PS. Popcorn is OK. No popping beer cans tho... you'd spook 'em.

:popcorn1
 
tfk said:
Folks,

 :eusa_shhh: Shhhhhhhhh.....

If you want to observe them in their native habitat, you must learn to sit very, very quietly...


Tom

PS. Popcorn is OK. No popping beer cans tho... you'd spook 'em.

:popcorn1
Click to expand...

Best be careful though T. If they detect you you may get savaged (yet again).
 
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bill smith said:
No.sorry. Do you have any idea why they would have dropped the penthouses first ? If there is no good structural reason could it be that there was something in the penthouses that they did not want on the top of the pile ?
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You made my day! Probably some dirty elevator engine or something like that. And that's why the pulled columns 81,80 and 79 first, you think? Larry, Larry, Larry...
 
So you think that this Larry person personally "pulled" (whatever the hell that means) the columns all by himself?
 
achimspok said:
Not a very good idea.
[qimg]http://img714.imageshack.us/img714/6940/dropdeform.gif[/qimg]
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Ah yes I see, like here:



Glad it was dustified when it reached the car, otherwise it would probably have been destroyed.

Enough derailing for now. I'll grab some popcorn.
 
achimspok said:
You made my day! Probably some dirty elevator engine or something like that. And that's why the pulled columns 81,80 and 79 first, you think? Larry, Larry, Larry...
Click to expand...

What could it be though ? Something with a distinctive shape and colour probably. Maybe many of them. Enough to set tongues wagging anyway. Better at the bottom of the pile than at the top in full view.

On the other hand maybe it made sense to demolish those particular columns first for purely structural reasons.
 
Can you explain that a little better. I recognize the words, but in that order they make little sense.
 
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